1. Field of the Invention
The present invention relates to a fuel cell.
2. Description of the Related Art
A conventional fuel cell includes a laminated, plate-shaped membrane electrode assembly and first and second separator plates, which sandwich the membrane electrode assembly therebetween. The membrane electrode assembly includes an electrolyte; first and second electrode layers sandwiching the electrolyte therebetween; and first and second gas-diffusion layers disposed outside the electrode layers, respectively, relative to the electrolyte. Each gas-diffusion layer is generally made of a carbon paper. However, carbon paper is typically low in strength and surface pressure resistance, and moreover, is brittle. Therefore, during formation of a stack in the conventional fuel cell, control of the surface pressure involving contact resistance reduction is extremely difficult to accomplish.
In order to eliminate such a disadvantage, Japanese Patent No. 2000-58072 disclosed a gas-diffusion layer formed from a metal mesh or a porous metallic material.
However, in such a conventional gas-diffusion layer, because the diameter of fine pores in a surface of the gas-diffusion layer on a side contacting an electrode is relatively large, portions of an electrode layer and an electrolyte bite deeply into the fine pores due to a pressing force that is generated during formation of a stack, exposing the electrolyte to damage from the gas-diffusion layer.